Radiator Probs

I have a coolant leak on my 2000 dodge stratus, I can not tell, nor could the boys that changed my oil, where the leak was coming from, ie: hoses or the radiator. I went to my family's trusted mechanic and they quoted me about $400 - $450 labor and parts to replace it. My husband said this is too high, however I am reluctant to take his word. Any advice?